On May 4, 1493, then-pope Alexander VI issued what was known as a papal bull – the Inter caetera – which set off the European conquest of the New World at the expense of indigenous tribal people. On May 4 of this year, Steven Newcomb, co-founder of the California-based Indigenous Law Institute, met with Pope Francis and called on him to formally revoke the bull.

“We are also calling on them to formally acknowledge that it was issued and that the system of thought and behavior that was unleashed on the planet,” he said. Newcomb's Shawnee and Lenape ancestors were among the hundreds of tribal groups that lost land and other rights to European settlers.

Papal bull Inter Caetera, 1493. With this decree, Pope Alexander VI gave Spain a free hand to colonize the Americas—to convert Native peoples to Catholicism and subjugate them to European monarchs.

Throughout the Middle Ages, the pope was believed to be not only the head of the Christian Church, but God’s representative on Earth. Kings and popes often competed for authority, but if a papal bull worked in a king’s favor, he was likely to follow it.

“Basically, the pope was granting Portugal the right to do anything it wanted to do,” said Robert J. Miller, professor of law at Arizona State University’s Sandra Day O’Connor School of Law and a member of the Eastern Shawnee tribe.

Portugal had been focused on exploring and plundering Africa’s west coast, but when Christopher Columbus claimed the West Indies for Spain, Lisbon was outraged, believing its rights to discovery and colonization extended globally.

That’s when Pope Alexander IV issued the infamous Inter caetera. He drew a line midway across the Atlantic Ocean, giving Spain discovery rights to the west of the line and Portugal all lands to the east.

Not to be outdone, King Henry VII in 1497 authorized explorer Henry Cabot to sail west and claim new lands for England.

“Cabot stepped ashore in Newfoundland and went through the same charade of claiming the land for England that Columbus had for Spain,” said Miller. “They didn’t care that there were indigenous people there because since they weren’t Christian, they weren’t considered to be humans.”

A map of the Americas in 1562, a collaboration by 16th Century Spanish cartographer Diego Gutiérrez and noted Antwerb engraver Hieronymus Cock.

Evidence in US law

Taken together, the Inter caetera and related bulls established the “Doctrine of Discovery,” a legal and ideological concept Christian Europe used to justify its actions. Miller believes doctrine was incorporated into American colonial, state and federal laws, he said, and is part of a U.S. policy in place today.

He said the language of the doctrine can be found in modern case law. In 1954, the Tee-Hit-Ton Indians sued the U.S. for lumber taken from their ancestral lands in Alaska. The court dismissed the suit, arguing that because the “Tee-Hit-Tons were in a hunting and fishing stage of civilization,” they had only a limited right of occupancy, and therefore the U.S. was not required to reimburse them.

“American Indian tribes in the United States own 56 million acres [23 million hectares] of land today in trust with the United States,” Miller said. “But the tribes do not really own the fee simple absolute title to these lands the way you or I do when we buy homes,” said Miller.

Robert T. Coulter, director of the non-profit Indian Law Resource Center and member of the Citizen Potawatomi Nation, says the Doctrine of Discovery has never been part of United States law - in spite of what courts and government officials may claim.

“Statements of the pope are not law. Nor are the statements of a particular king,” he said. “International law isn’t created that way and it never was. Professor Miller is making a legal argument that hundreds of tribes don’t own the land that they own. And this makes it even more difficult for Indians to hang on to their lands.”

The U.S. Bureau of Indian Affairs defines a federal Indian reservation as “an area of land reserved for a tribe or tribes under treaty or other agreement with the United States…where the federal government holds title to the land in trust on behalf of the tribe."

Coulter responds by saying, “The United States imposes all kinds of unjustifiable restrictions on what tribes can do with their land. That’s true, but it doesn’t have anything to do with discovery. I think the government’s legal basis for that is near zero.”

Pope Francis making as speech during a World Meeting of Popular Movements in Santa Cruz, Bolivia, July 9, 2015. The pope apologized for the sins committed by the Church against indigenous populations during the age of exploration and conquest of the New W

As for the Vatican, in 2010 its ambassador to the United Nations told the United Nations Permanent Forum on Indigenous Issues that the papal bull Inter caetera was rescinded by subsequent bulls and treaties over the centuries and is today merely a “historic remnant with no juridical, moral or doctrinal value.”

Furthermore, he said, if nations set the Doctrine of Discovery as a legal precedent, refuting it is a matter for their lawmakers.

In a landmark speech in July 2015, Pope Francis acknowledged the “grave sins” on the part of the Church in colonial times.

“I humbly ask forgiveness, not only for the offense of the Church herself, but also for crimes committed against the native peoples during the so-called conquest of America,” he said.